The present invention relates to a synchronous machine, in particular a generator or a motor for a motor vehicle.
In particular, it relates to a synchronous machine which has an excitation system with a plurality of electrically excited individual poles in the stator or rotor, preferably in form of claw poles which are excited by at least one common excitation coil, wherein for compensation of the magnetic stray flux, permanent magnets are arranged in the free spaces between the claw poles which are oriented toward one another and alternatingly nested in one another, on the pole plates arranged on the ends of the stator or rotor.
Such a synchronous machine is disclosed for example in the German patent document DE 89 05 353. The permanent magnets which are located in the free spaces between the claw poles of a rotor are magnetized tangentially so that they compensate the stray flux between the neighboring claw poles and so that the power of the synchronous machine is increased. The permanent magnets are supported radially on the non-magnetic holding plates, which are inserted and fixed in the peripheral, substantially axially extending recesses, while the permanent magnets are placed on the facing side of the neighboring claw poles.
In this known synchronous machine, the insertion of the permanent magnets requires a substantial mounting expense and moreover the permanent magnets are not sufficiently fixed in the axial direction of the rotor. Also, the claw poles with their recesses for the holding plates have a complicated construction.